The "chemical earmuffs" that could bring hearing protection in a pill



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A molecular route to a drug that provides hearing protection—"chemical earmuffs"—may have been discovered by a team of biologists at the University of Iowa (UIowa) and Washington University, St. Louis.

Already successfully tested by the researchers on mice, the drug they used appears to prevent hearing damage but still allow sound to be heard. It works by selectively blocking receptors involved in the hair-cell-to-nerve-cell transmission, singling out those receptors that lack a protein called GluA2. These receptors are responsible for synaptopathy, or hearing loss caused by irreparable damage to the synapses. The drug blocked these in the mice, but researchers found that GluA2-remaining receptors picked up the slack.

"It wasn't just putting earmuffs on; these earmuffs prevent the damage caused by loud sounds but don't muffle the sound," says Steven Green, professor in the Department of Biology at UIowa and corresponding author on the study, published in the journal Proceedings of the National Academy of Sciences.

Caution is advised, however, about speculation for use of a possible drug outcome from the research stretching to scenarios such as soldiers taking a drug before expected loud missions but still being able to hear commands. "Permanent hearing damage can be caused by noise levels that have been considered 'safe', and people need to be careful about noise exposure because we can't yet repair synapses or regenerate hair cells," Green says. "Our chemical earmuffs are, currently, just an indication of the direction research can go, not yet a proven, safe means of protection in humans."

Nevertheless, the US Department of Defense is interested enough in the idea to fund it, along with money from the National Institutes of Health and the American Hearing Research Foundation.

Source: Science Daily